Sensor and method for determining fractions of oil, water, and solids in drilling fluid in real time

1 . An apparatus for estimating a fraction of oil, water, and solids of a drilling fluid, the apparatus comprising:

a conduit containing the drilling fluid;

an electromagnetic sensor in electromagnetic communication with the drilling fluid in the conduit, the electromagnetic sensor comprising a coil and electronics coupled to the coil, the electronics generating current in the coil inducing eddy currents in the drilling fluid and measuring an energy loss due to the eddy currents, the energy loss being correlated to a combined water and solids fraction;

a conductivity sensor comprising electronics coupled to a conductivity probe in conductive communication with the drilling fluid to provide a conductivity value;

a density sensor comprising electronics coupled to a Coriolis sensor in communication with the drilling fluid to provide a density value;

a processing system determining the fraction of oil, water, and solids in the drilling fluid using the combined water and solid fraction and at least one of the conductivity value from the conductivity sensor or the density value from the density sensor, the processing system having a first input coupled to the electromagnetic sensor, at least one of a second input coupled to the conductivity sensor or a third input coupled to the density sensor, and an output providing the fraction of oil, water, and solids, wherein the processing system comprises an input port configured to receive initial component fractions for the oil, water, and solids and an initial density value of the drilling fluid; and

a controller coupled to the output of the processing system, the controller having an output coupled to a drilling fluid additive control device controlling an additive to be added to the drilling fluid based on the fraction of oil, water, and solids of the drilling fluid;

wherein the processing system is configured to at least one of: (i) to attribute a change in the combined water and solids fraction to a change in the water fraction from the initial water fraction in response to a decrease in the density value, determine the solids fraction by subtracting the current water fraction from the combined water and solids fraction, and determine the oil fraction as the remainder making up the drilling fluid; or (ii) to attribute a change in the combined water and solids fraction to a change in the solids fraction from the initial solids fraction in response to an increase in the density value, determine the solids fraction by subtracting the water fraction from the combined water and solids fraction, and determine the oil fraction as the remainder making up the drilling fluid.

2 . The apparatus according to claim 1 , further comprising a housing containing the conduit, the electromagnetic sensor and at least one of the conductivity sensor or the density sensor.

3 . The apparatus according to claim 2 , wherein the processing system is further disposed in the housing.

4 . The apparatus according to claim 1 , wherein the processing system converts the conductivity value to a water fraction using a conversion factor, determines the solids fraction by subtracting the water fraction from the combined water and solids fraction, and determines the oil fraction as the remainder making up the drilling fluid.

5 . The apparatus according to claim 1 , wherein the drilling fluid additive control device comprises one of a flow control valve or a metering pump.

6 . The apparatus according to claim 1 , wherein the drilling fluid flows continuously through the conduit while being sensed.

7 . A method for estimating an oil, water, and solids fraction of a drilling fluid, the method comprising:

containing the drilling fluid in a conduit;

sensing a combined water and solid fraction in the drilling fluid using an electromagnetic sensor in electromagnetic communication with the drilling fluid in the conduit;

sensing a water fraction of the drilling fluid using a conductivity sensor in communication with the drilling fluid in the conduit or a density value of the drilling fluid using a density sensor in communication with the drilling fluid in the conduit;

determining the fraction of oil, water, and solids in the drilling fluid using the combined water and solid fraction and the water fraction; and

controlling an additive to be added to the drilling fluid based upon the fraction of oil, water, and solids in the drilling fluid;

wherein the method further comprises receiving initial component fractions for the oil, water, and solids and an initial density value of the drilling fluid and at least one of: (i) determining a change in the density value from the initial density value, attributing a change in the combined water and solids fraction to a change in the water fraction in response to a decrease in the density value with respect to the initial density value, determining the solids fraction by subtracting the current water fraction from the combined water and solids fraction, and determining the oil fraction as the remainder making up the drilling fluid; or (ii) determining a change in the density value from the initial density value, attributing a change in the combined water and solids fraction to a change in the solids fraction in response to an increase in the density value with respect to the initial density value, determining the solids fraction by subtracting the water fraction from the combined water and solids fraction, and determining the oil fraction as the remainder making up the drilling fluid.

8 . The method according to claim 7 , wherein sensing a combined water and solid fraction in the drilling fluid comprises inducing eddy currents in the drilling fluid by generating current in a coil wrapped around the conduit and measuring a power energy loss due to the eddy currents, the power energy loss being correlated to a combined water and solids fraction.

9 . The method according to claim 7 , wherein sensing a conductivity value the drilling fluid comprises emitting a microwave signal into the drilling fluid, receiving a return signal, determining an amplitude and/or phase difference between the emitted signal and the return signal, and correlating the amplitude and/or phase difference to the conductivity value.

10 . The method according to claim 7 , further comprising converting the conductivity value to the water fraction.

11 . The method according to claim 7 , wherein sensing a density value comprises using a Coriolis sensor in communication with the drilling fluid.

12 . An apparatus for estimating a fraction of oil, water, and solids of a drilling fluid, the apparatus comprising:

a conduit containing the drilling fluid;

an electromagnetic sensor in electromagnetic communication with the drilling fluid in the conduit, the electromagnetic sensor comprising a coil and electronics coupled to the coil, the electronics generating current in the coil inducing eddy currents in the drilling fluid and measuring an energy loss due to the eddy currents, the energy loss being correlated to a combined water and solids fraction;

a conductivity sensor comprising electronics coupled to a conductivity probe in conductive communication with the drilling fluid to provide a conductivity value;

a density sensor comprising electronics coupled to a Coriolis sensor in communication with the drilling fluid to provide a density value;

a processing system determining the fraction of oil, water, and solids in the drilling fluid using the combined water and solid fraction and at least one of the conductivity value from the conductivity sensor or the density value from the density sensor, the processing system having a first input coupled to the electromagnetic sensor, at least one of a second input coupled to the conductivity sensor or a third input coupled to the density sensor, and an output providing the fraction of oil, water, and solids; and

a controller coupled to the output of the processing system, the controller having an output coupled to a drilling fluid additive control device controlling an additive to be added to the drilling fluid based on the fraction of oil, water, and solids of the drilling fluid;

wherein the processing system is configured to receive data from the electromagnetic sensor, the conductivity sensor, and the density sensor and to determine first fractions of the oil, water, and solids using the data from the electromagnetic sensor and data from the conductivity sensor and second fractions of the oil, water, and solids using the data from the electromagnetic sensor and data from the density sensor.

13 . The apparatus according to claim 12 , wherein the processing system is configured to determine a difference between the first fraction components and the second fraction components and provide an alert signal in response to the difference exceeding a threshold value.

14 . A method for estimating an oil, water, and solids fraction of a drilling fluid, the method comprising:

containing the drilling fluid in a conduit;

sensing a combined water and solid fraction in the drilling fluid using an electromagnetic sensor in electromagnetic communication with the drilling fluid in the conduit;

sensing a water fraction of the drilling fluid using a conductivity sensor in communication with the drilling fluid in the conduit and a density value of the drilling fluid using a density sensor in communication with the drilling fluid in the conduit;

determining the fraction of oil, water, and solids in the drilling fluid using the combined water and solid fraction and the water fraction; and

controlling an additive to be added to the drilling fluid based upon the fraction of oil, water, and solids in the drilling fluid;

wherein the method further comprises: determining first fractions of the oil, water, and solids using the combined water and solids fraction and the conductivity value and second fractions of the oil, water, and solids using the combined water and solids fraction and the density value; and sending a user an alert signal in response to a difference between any of the first fraction components and the corresponding second fraction components exceeding a threshold value.